3维电子沙盘在水库防洪调度中的运用     

周学龙  吕华新 《测绘与空间地理信息》2013,(8):132-134

利用3维电子沙盘,结合地理信息系统的分析能力,开发奉化亭下水库3维防洪调度仿真系统。本文详细阐述了系统的总体技术方案、总体框架及关键技术,实现了水库3维淹没分析、库容计算等具体功能。  相似文献   

Statistical determination of significant curved I-girder bridge seismic response parameters     

Junwon Seo 《地震工程与工程振动(英文版)》2013,12(2):251-260

Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.  相似文献   

Effects of land use,slope gradient,and soil and water conservation structures on runoff and soil loss in semi-arid Northern Ethiopia     

Gebeyehu Taye  Jean Poesen  Bas Van Wesemael  Matthias Vanmaercke  Daniel Teka  Jozef Deckers 《自然地理学》2013,34(3):236-259

April lightning production in Richmond County, Georgia, from 1995 to 2003 is considered with regard to the associated risk to golfers and spectators at the Master's Golf Tournament and courses throughout the county. An examination of the April lightning climatology of Georgia, focusing on Richmond County, reveals a minimum in lightning activity during the time of the tournament (the first full week of April). A discriminant analysis of Richmond County lightning production utilizes several meteorological variables in order to discern between three categories of April lightning days: little or no lightning activity, minimal lightning activity, and high lightning activity. The analysis distinguishes relatively well between the categories with only 13.5% of the events misclassified. A composite regional analysis of the three lightning categories illustrates the environmental differences between these events. Although the little or no lightning and high lightning categories are somewhat similar environmentally, the intensity of features separates these events and allows for interpretation. The statistical and synoptic analyses together emphasize the importance of low-level instability and frontal proximity and intensity in enhancing lightning production in thunderstorms during April in and surrounding Richmond County. A multitude of meteorological conditions can lead to thunderstorm development. Localized studies of these environments, especially during times of major outdoor sporting events, are needed to help mitigate the risk associated with lightning.  相似文献   

Following the curve? Reviewing the physical basis of the SCS curve number method for estimating storm runoff     

Mike Kirkby  Artemi Cerdà 《水文研究》2021,35(11):e14404

Less attention has been paid to runoff generation from semi-arid than from humid-temperate catchments. The SCS curve number approach is simple to apply and widely used, but lacks physical underpinning. Here output from a runoff generation models is compared with data from field measurements, making use of 11 years data from rainfall and runoff events at the Sierra de Enguera Soil Erosion Experimental Station in Eastern Spain. Runoff from natural rainfall events was monitored for 10 years on bare plots of 1–16 m length. The largest storm event was of 142 mm, generating runoff of up to 115 mm on the smallest plots. The model presented simulates overland storm flow on a sloping rough and unvegetated surface, representing an area of 320 × 320 m. Green-Ampt infiltration constants are randomly assigned to each cell in a 128 × 128 grid, and rectangular storms applied at a range of total amounts and intensities to simulate runoff at each transect across the area. A simple algebraic expression is developed to estimate total runoff and storage in terms of storm size and duration, and plot length, with parameters that reflect infiltration behaviour, and this expression is compared with the SCS curve number approach. For the very largest storms, both expressions converge asymptotically towards 100% runoff, but the revised expression greatly improves estimates of runoff from smaller events. Output of these simulations is compared with measured storm runoff data on bare runoff plots at the Sierra de Enguera experimental Station in SE Spain and gives further support to the proposed expression for storm runoff.  相似文献   

基于Skyline的三维城市模型数据库管理系统设计与实现   总被引：1，自引：0，他引：1  

黄梦龙 《测绘与空间地理信息》2014,(8):133-135

城市三维模型在城市规划、建设等方面得到了广泛的应用。本文介绍了城市三维模型管理的现状,分析了三维城市模型建库管理的需求,基于Skyline三维地理信息系统和ArcGIS Engine,设计了三维模型数据库的存储结构,并开发了三维模型数据库管理系统,实现了三维模型的建库管理。  相似文献   

基于岩性划分的渗透率预测模型研究     

陈德元  谭成仟  徐振永  苏超 《地球科学与环境学报》2007,29(2):158-161

针对常规渗透率解释模型预测的渗透率误差较大,难以满足油田开发中后期油藏数值模拟需求的难题,在分析渗透率中储层岩性、孔隙度、泥质含量诸影响因素的基础上,提出先使用测井曲线采用交会图技术识别出储层岩性,然后根据不同的储层类型,分别建立不同的渗透率预测模型。该方法综合考虑了储层岩性、孔隙度以及泥质含量对渗透率的影响,经过在秘鲁B油田中应用,取得了良好的地质效果,其渗透率预测精度得到了较大提高,为后期油田开发调整方案的制订奠定了良好的地质基础。  相似文献   

Slope runoff study in situ using rainfall simulator in mountainous area of North China     

XU Jing-Ji  YANG Cong  LIU Chang-Meng  SONG Xian-Fang  HU Shan-Shan  LI Fa-Dong  TANG Chang-Yuan 《地理学报》2009,30(4):461-470

Simulated rainfall is a valid tool to examine the runoff generation on the slope.13 simulated rainfall experiments with different rainfall intensities and durations are completed in a 5 m ×10 m experimental plot in mountainous area of North China.Simultaneously,rainfall,surface runoff,soil-layer flow,mantel-layer flow and soil moisture are monitored respectively.From the results,it is found that the hydrographs in all layers have the characteristics of rapid rise and fall.The recessions of surface flow and soil-layer flow are much faster than that of mantel-layer flow.Surface flow,the main contributor,makes up more than 60% of the total runoff in the study area.It even exceeds 90% in the cases of high intensity rainfall events.Runoff coefficient(ratio of total runoff to rainfall amount) is mainly influenced by rainfall amount,rainfall intensity and antecedent soil moisture,and the relationship can be well expressed by a multiple linear regression function α = 0.002P + 0.182i + 4.88Wa-0.821.The relation between the rainfall intensity and the lag time of three flows(surface runoff,soil-layer flow and mantel-layer flow) is shown to be exponential.Then,the result also shows that the recession constant is 0.75 for surface runoff,is 0.94 for soil-layer and mantel-layer flow in this area.In this study area,the dominant infiltration excess runoff is simulated by Horton model.About 0.10 mm/min percolation is observed under the condition of different rainfall intensities,therefore the value is regarded as the steady infiltration rate of the study area.  相似文献   

Notes     

《The Journal of geography》2012,111(6):279-288

Abstract

The concept of correlation is becoming increasingly important to students of all ages as the use of electronic data base technology becomes more common. Data maps offer a significant and new format for secondary students to use along with tables of values and scatter plots as they learn and apply the correlation concept. Data maps are particularly effective in promoting the interdisciplinary treatment of important content by allowing students to interpret social or physical relationships within the geographic context in which they arise.  相似文献   

Milwaukee     

《The Journal of geography》2012,111(2):72-73

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